Gualicho is an interesting and somewhat rare word, especially in mainstream music. It refers to a hex, spell, or charm, often with a connotation of witchcraft or folk magic, particularly in some South American regions like Argentina.
In the song, the artist sings, "Me tienes embobao, ¿qué me hiciste?, ¿Un gualicho?" (You have me dazed, what did you do to me? A spell?). He uses it to express how captivated and enchanted he feels by someone, as if they've cast a spell on him, making it a memorable and culturally rich word choice.
The whole song is one invitation, aimed at someone who has just been let down. It opens with a diagnosis rather than a chat-up line: "Te hicieron daño, ahora estás revelada" (They hurt you, now you've turned rebellious) and "No eras así, se ve que andas despechada" (You didn't used to be like this, you're clearly heartbroken). His answer is a night out rather than sympathy — "Ponete linda que te voy a sacar" (Get dressed up, I'm taking you out). The chorus makes the argument explicit: "Lo que yo voy a enseñarte / no se aprende en una biblioteca" (What I'm going to teach you, you don't learn in a library), and "aquí todo el mundo peca" (here everybody sins) is offered as reassurance — nobody in the room is in a position to judge her.
Halfway through, the setting turns unmistakably Argentine. He orders Fernet ("Tráeme el Fernet"), he is at the boliche rather than a club, and "los guacho' y las guacha'" is the local way of naming the guys and girls he is out with. The boast "El único país que tiene a Dios en el cielo y en la tierra" (The only country with God in heaven and on earth) is a football joke, the god on earth being Maradona. Even the flirting is regional: "¿qué me hiciste?, ¿Un gualicho?" (what did you do to me? Put a spell on me?) uses a Rioplatense word for a love charm. The last few lines are just producer tags — Migrantes, Nio, DeMasters — the crew signing the record.